Histotripsy and the Abscopal Effect
The Home Run: non-invasive tumor destruction and systemic immune response.
For some patients, Histotripsy and a stimulated immune system can elicit the Abscopal effect causing regression of many if not all of their tumors.
Histotripsy
Histotripsy is the first non-invasive, non-ionizing and non-thermal ablation interventional radiologic technology of focused ultrasound delivered from outside the body by guided real-time imaging. Histotripsy mechanically destroys tissue through high amplitude, very short pulses that destroy tumors by creating bubbles that rupture the tumor cells, which then liquefy, while leaving normal cells undamaged.
It was approved by the FDA for clinical use in October 2023, and in November 2024 the Veterans Administration awarded a $90 million contract to develop histotripsy programs at key VA hospitals.
Histotripsy was developed at the University of Michigan in the early 2000s, and has been studied on benign prostatic hyperplasia (BPH), prostate cancer, renal masses, renal calculi, blood clots, calcified aortic stenosis, fetal tumors and congenital heart diseases, uterine fibroids, bone tumors, although it has primarily been approved for liver tumors world-wide.
The Abscopal Effect
The Abscopal Effect is the shrinking or disappearance of tumors in parts of the body that were not the direct target of local therapy, as well as the regression of the target tumor lesion. It is believed that the effect is mediated by the immune system, which identifies the cancerous cells and then attacks any of the same cancer cells wherever they are found in the body.
Adding drugs called immune checkpoint inhibitors, or otherwise boosting the immune system, can enhance the abscopal effect. As of 2022, the most promising data with combined immunotherapy and radiation therapy has been found in patients with lung cancer and melanoma.